function cal(b)
back={}
front={}
for i=1,b do
	if i%2==0 then
		table.insert(back,b+1-i)
	else
		table.insert(front,1+i)
	end
	
end
print("you may copy this line to print")
		s=table.concat(back,",")
		print(s)
		s=table.concat(front,",")
		print(s)
end

print("enter an number, must be multiplication of 8")
a=io.read("*number")
cal(a)
